Depends. Do you like the extra passive damage, or do you like extra procs of pyroblast?

1 Intellect=1 Spell Power
1 Intellect=0.00039% Crit

So 275 Intellect = 275 Spell Power and 0.1 % crit, making a loss of 0.9% crit and slightly less procs.

/grain of salt: Haven't played my mage in pandaland because she is an alt, but plan to soon.

Pretty sure 1 Intellect is 1.155 spellpower. It took me a while to find out the number a week or two ago when I was changing my gear around and noticed it wasn't a 1:1 ratio. Not sure about the crit from 1 intellect though.

You can see that Worgen wins out by a small margin of a couple hundred dps. If you want more answers to similar questions, I'd recommend picking up SimulationCraft. It is a very useful program and one that I spent a good amount of time using whenever I'm trying to decide for the next piece of loot I'm going to pursue or any similar question.